Peyton Rous, in full Francis Peyton Rous (born October 5, 1879, Baltimore, Maryland, U.S.—died February 16, 1970, New York, New York) American pathologist whose discovery of cancer-inducing viruses earned him a share of the Nobel Prize for Physiology or Medicine in 1966.

...Vilhelm Ellermann and Oluf Bang, reported that leukemia could be transmitted in chickens by means of a cell-free filtrate obtained from a chicken with the disease. In 1911 American pathologist Peyton Rous demonstrated that a sarcoma (another type of cancer) could be transmitted in chickens through a cell-free extract. Rous discovered that the sarcoma was caused by a virus—now called...

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(1879-1970), U.S. pathologist. His research on tumor-inducing viruses earned Francis Peyton Rous a share of the 1966 Nobel prize for physiology or medicine. Born on Oct. 5, 1879, in Baltimore, Md., Rous received a bachelor of arts and a medical degree from Johns Hopkins University. In 1909 he joined the Rockefeller Institute for Medical Research (now Rockefeller University) in New York City. While researching tumors in rodents, he began to study chickens as well. By 1910 he had discovered a cancer that was caused by a virus. The revolutionary results of his work were at first disbelieved but later came to be appreciated.